Due to the rapid expansion of the Department and the increase in resulting electron microscopy studies, the present EM facilities have become inadequate for the efficient and timely execution of the studies funded by NIH within the department. The present facilities include a JEOL 100CX electron microscope (purchased in 1980) and a Philips 200 electron microscope (purchased in 1964). The latter instrument has been in operation for only 50% of the year due to breakdown, and long term continued use of this microscope for research projects appears unlikely. These two electron microscopes currently serve the research needs of the Department of Cell Biology and Anatomy which presently includes 12 full-time faculty members. The addition of the JEOL 1200 EX electron microscope with STEM/SCAN is necessary both to replace the Philips 200 and to make possible new NIH studies of Dr. Brinkley which necessitates the use of STEM/SCAN, a method provided by neither of our current instruments. The major users group consist of Drs. Brinkley, Mayne, Wyss, Abrahamson, Davis and Geisert each of whom is a principle investigator of an NIH funded study which necessitates the use of the electron microscope as a primary research tool. Up to 25% of time on the new instrument will be made available to the other 4 members of the departmental faculty who use the electron microscope in their research, as well as the 10 new members of the faculty who will be recruited over the next 4 years. The use and maintenance of the new instrument will be monitored by a users group consisting of the P.I., Dr. Wyss, one other member of the primary user group elected by the group, and one other member of the department elected by the faculty.